I'd say Meta tags should be kept to technical info; that is, tags describing actual content of the image should stay in general. Various *_request, bad_*, *_sample, automated tags, format-related tags, etc, most of which are already in the list. For that reason, I'm against even including tags like text in the list, strongly against including incest or cheating, but for including game_cg. Also propose including novel_cover, since that's only for actual novel covers, not "mock-up" ones.
How about establishing some hard guidelines? I propose that meta tag should, in general, fall in one of those categories:
- Information describing image as a digital file: dimensions, filesize, formats
- Information about image source: various bad_id, *_reward, protected_link, inactive_account, etc. game_cg or screenshot would apply too.
- Information about other available versions of the image: revision, *_available, *_sample
- Information about third-party modifications: photoshop, cropped, stitched, 3rd-party-watermark, etc. hard-translated would fall in here, too.
- Technical tags necessary for danbooru functioning: *_request, check_*, commentary, translated, replaceme, the dreaded tagme.
- Information about reference or derivative work: derivative_work, reference_work, photoreference, vector_trace etc.
Other tags would be added on case-but-case basis, but should have no direct relation to image content. I actually feel conflicted about animated tag, but maybe it's better to have it as an exception.